Method of manufacturing a launder and launder

ABSTRACT

A method of manufacturing a launder ( 1 ) to be used in co-operation with a solvent extraction settler ( 2 ) comprises manufacturing at the site of manufacture, such as in an engineering workshop, a plurality of self-supporting launder element modules ( 3 ), each having exterior dimensions, strength and handling and securing means ( 4 ) conforming to shipping container standards, transporting the launder element modules ( 3 ) to the site of installation as normal freight by transport equipment, such as trucks, trailers and container ships, capable of handling and transporting shipping container standard compatible units, and assembling at the site of installation the launder element modules ( 3 ) into a module group ( 5 ) forming a complete launder. The launder ( 1 ) comprises a launder module group ( 5 ) consisting of self-supporting launder element modules ( 3 ), each having exterior dimensions, strength and handling and securing means ( 4 ) conforming to shipping container standards to enable shipping container standard compatible transportability.

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing a launder tobe used in co-operation with a solvent extraction settler adapted forhydrometallurgical liquid-liquid extraction processes. Further, theinvention relates to a launder.

BACKGROUND OF THE INVENTION

In a typical mixer-settler, in the first step, the aqueous and organicphases are pumped into a mixer or mixers in order to achieve a uniformliquid-liquid dispersion and a small droplet size. In the VSF®technology (stands for Vertical Smooth Flow) developed by the applicantthis first step is performed in a pump-mixer called Dispersion OverflowPump (DOP®) (disclosed e.g. in U.S. Pat. No. 5,662,871) and in a set oftwo SPIROK® helical mixers (disclosed in e.g. U.S. Pat. No. 5,185,081).After mixing, the dispersion is fed into a settler. The settler istypically a large tank which is square in plan and its square area isabout several hundred square meteres. Dispersion is fed into the settlerat the front end of the settler. A distributor fence is arranged at thefeed end of the settler to distribute the flow of the dispersion to thewhole width of the settler. In the settler, the dispersion moves towardsthe settler back wall and, at the same time, the phases separate bygravity into two layers with a dispersion band remaining between them.Typically, separation fences are arranged in the settler tank to enhancecoalescence of the dispersion. In the VSF® technology the separationfences are so-called DDG® fences (Dispersion Depletor Gate) (disclosede.g. in U.S. Pat. No. 7,517,461).

At the rear end of the settler, an adjustable weir and launders are usedto control the vertical position of the phase interface anal. to collectand discharge both phases, respectively. Arrangements of settlers andlaunders are disclosed also e.g. in documents WO 97/40899, WO 97/40900,WO 97/40901, WO 2009/063128 A1 and WO 2010/097516 A1.

The known launder typically comprises two launders arranged in parallelside-by-side. One of the launders is an overflow launder arranged toreceive the lighter solution (e.g. organic phase) as an overflow fromthe settler and the other launder is an underflow launder arranged toreceive the heavier solution (e.g. aqueous solution) as an underflowfrom the settler. The launder arrangement is made of a fiber-reinforcedplastic composite by hand laminating, or by filament winding asdescribed in WO 2010/097516 A1. WO 2009/063128 discloses that the wholelaunder is manufactured at a place of manufacture, such as in anengineering workshop, into a self-supporting subassembly which istransferred as a uniform entity to the site of installation where i isinstalled on the bottom of the settler.

So far, a solvent extraction plant including the launder has beenproject specified. In each case the out of the plant and the equipmenthave been unique. There has not been a possibility for theproductization of launders. The present launders have nonstandardtransport dimensions requiring oversize transport which is expensive.Launders known in the prior art also require most of the constructionwork to be done at the site. This causes problems because of the crucialinfluence of local factors. It may be difficult to get local suppliers.It has been difficult to control the quality of the site work by localsuppliers.

Further, the maintenance of the present launders requires a longdowntime of the whole solvent extraction settler with which the launderrequiring maintenance is connected.

OBJECT OF THE INVENTION

The object of the invention is to eliminate the disadvantages mentionedabove.

In particular, it is an object of the present invention to provide amethod of manufacturing a modular launder and a modular launder in whichthe individual, in workshop pre-fabricated,—container compatible launderelement modules provide shipping container standard compatibletransportability, stacking capability, modularity and scalability of thelaunder design.

It is also an object of the present invention to provide a method formanufacturing a modular launder and a modular launder which enable thatthe construction work at the installation site may be kept at a minimum,resulting in low installation costs and good quality.

Further, it is an object of the present invention to provide a launderwhich can be easily disassembled and re-located.

Further, it is an object of the present invention to provide a launderwhich can be first delivered as a small-scale test or pilot launder fora pilot solvent extraction plant and later expanded into a launder for afull size solvent extraction plant.

Further, it is an object of the present invention to provide a launderwhich can be easily maintained.

SUMMARY OF THE INVENTION

According to a first aspect, the present invention provides a method ofmanufacturing a launder to be used in co-operation with a solventextraction settler adapted for hydrometallurgical liquid-liquidextraction processes, in which method the launder is installed at thedischarge end of the settler. The method comprises the steps ofmanufacturing at the site of manufacture, such as in an engineeringworkshop, a plurality of self-supporting launder element modules eachhaving exterior dimensions, strength and handling and securing meansconforming to shipping container standards; transporting the launderelement modules to the site of installation as normal freight bytransport equipment, such as trucks, trailers and container ships,capable of handling and transporting shipping container standardcompatible units; and assembling at the site of installation the launderelement modules into a module group forming a complete launder.

According to a second aspect, the present invention provides a launderto be used in co-operation with a solvent extraction settler adapted forhydrometallurgical liquid-liquid extraction processes. The laundercomprises a launder module group consisting of self-supporting launderelement modules each having exterior dimensions, strength and handlingand securing means conforming to shipping container standards to enableshipping container standard compatible transportability.

The advantage of the invention is that the launder element modules canbe manufactured in the factory environment, which is different from theinstallation site environment, which provides good quality. The laundermodules being shipping container standard compatible units provides allbenefits of the normal shipping containers: they can be handled withnormal transport equipment and there is no need for oversize transportequipment. The launder element modules having dimensions, strength andhandling and securing means conforming to—shipping container standardsthus have all the benefits of the transportability of normal shippingcontainers. The launder element modules can be transported on land bytrucks and trailers and with container ships by sea. In ports they canbe handled with normal container handling equipment. A complete launder,which may comprise a plurality of launder element modules, can beshipped in one delivery. The modular structure enables flexible capacitysince more capacity can be built while the solvent extraction plant isrunning by increasing the number of modules. The launder can easily bere-located and recycled by disassembling the modules at one site andreassembling them into a launder located at another site.

In an embodiment of the launder, the launder element module conforms toISO shipping container standards to enable ISO shipping containerstandard compatible transportability.

In an embodiment of the launder, the launder is arranged to feeddispersion to a solvent extraction settler. In an embodiment of thelaunder, the launder is arranged to receive and discharge solutionphases separated in the solvent extraction settler. Preferably bothfeeding and discharging functions are combined into a common launderelement module, discharging functions serving one settler while thefeeding function is serving another settler.

In an embodiment of the launder, the launder element module comprises aself-supporting framework structure having a shape of a rectangularparallelepiped with exterior dimensions and corner fittings conformingto shipping container standards, said corner fittings being attached toeach corner of the framework structure. Further, the launder elementmodule comprises a shell, said shell being supported inside theframework structure and forming at least a part of a flow path for thesolutions flowing in the launder.

In an embodiment of the launder, the launder element module conforms tostandard ISO 668 Series 1 “Freight containers—Classification, dimensionsand ratings”;

and the corner fittings conform to standard ISO 1161 Series 1 “Freightcontainers—Corner fittings—specification”. The strength of the modulesconforms to standard ISO 1496/1, Annex A. The strength of the cornerfittings conforms to standard ISO 1161.

In an embodiment of the launder, the shell is a tubular hollow body madeof a fibre-reinforced plastic composite. Preferably, the shell ismanufactured by filament winding technology. The shells connected toeach other form a gas-tight tubular flow path for the dispersion andseparated solutions. The gas-tight sealed construction eliminatesoxidation of the reagent by air, thus lowering make-up costs. Thegas-tight construction also decreases evaporation of the reagent,decreasing the release of Volatile Organic Compounds (VOC) to theenvironment. Manufacturing of the shell made of a fibre-reinforcedplastic composite by filament winding gives the shell a requiredstrength. The inner surface of the shell, which in operation comes tocontact with the dispersion and solvents, is inherently smooth becauseit is formed against a mandrel which has a smooth surface. The smoothsurface contacting the solvent flow minimizes local turbulences. Thesmooth surface also minimizes electrostatic charging and thereby reducesthe risk for fires due to igniting of volatile organic compounds in theinner atmosphere of the shell caused by electrostatic discharge.Electrostatic charging can also be reduced by adding carbon staplefibers to the plastic composite. Automated filament winding of the shellenables lower fabrication costs compared to any other manufacturingmethod, such as hand laminating.

In an embodiment of the launder, the module group comprises two or morelaunder element modules arranged in parallel and side-by-side with eachother. The side-by-side arrangement of the launder element modules isadvantageous because thereby the launder can be made compact and thefoundation can be implemented by a plurality of pillars supporting eachcorner of the launder element modules. One pillar may support one tofour corners of the modules.

In an embodiment of the launder, the launder element module comprises afirst shell to receive and conduct a light solution phase, and a secondshell to receive and conduct a heavy solution phase.

In an embodiment of the launder, the launder element module comprises athird shell adapted to feed dispersion to a next settler.

In an embodiment of the launder, the launder module group comprises aplurality of launder element modules. The first shells of the adjacentlyneighboring launder modules are abutting and connected to each other toform a first flow channel, and the second shells of the adjacentlyneighboring launder modules are abutting and connected to each other toform a second flow channel.

In an embodiment of the launder, the first shells are conical so thatthe sequentially connected first shells of the launder element modulesin the launder module group together form a conical first flow channel.

In an embodiment of the launder, the second shells are conical so thatthe sequentially connected second shells of the launder element modulesin the launder module group together form a conical second flow channel.

In an embodiment of the launder, the third shells are conical so thatthe sequentially connected third shells of the launder element modulesin the launder module group together form a conical third flow channel.

The first, second and third flow channels are all tubular closedcompartments which have many advantages. As an essentially closedstructure the inner atmosphere of the launders can be sealed from theouter atmosphere so that mist emissions cannot escape from theatmosphere in the interior of the launders to the outer atmosphere tocontaminate the air and worsen the working conditions. Likewise, thesurrounding air and e.g. insects and birds cannot enter the launders. Inaddition, when the lighter solution is an organic phase, the oxidationdegree of the organic phase decreases whereby solution costs arereduced. Further, in operation, the atmosphere of the launder above theliquid surface is flammable because it contains volatile organiccompounds which are released from the hydrocarbon based solvents. Thegas-tight closed compartments of the tubular shells provide fireprotection against accidental fires.

The conical first and second flow channels which form discharge channelsfor the lighter solution (normally organic) and the heavier solution(aqueous solution) have many inlets along their length. The crosssection of the conical first and second flow channels increases and thebottom is inclined downwards towards the first and second dischargeboxes. After each inlet the flow rate in the first and second flowchannels increases. In a conical launder the flow rate remains the samefor the whole length of the launder and no return eddies and standingflows are created. Thereby crud accumulation is avoided if the solutionscontain solids.

In an embodiment of the launder, the launder element module comprises afirst inlet pipe having a first end opening to the inner space of thefirst shell and a second end opening to the settler, the second endbeing adapted to receive the light solution phase as an overflow fromthe settler.

In an embodiment of the launder, the launder element module comprises asecond inlet pipe having a third end opening to the inner space of thesecond shell at a bottom of the second shell, and a fourth end openingto the settler, the fourth end being adapted to receive the heavysolution phase as an underflow from the settler.

In an embodiment of the launder, the overflow height position of thethird end of the second inlet pipe inside the second shell is adjustableby a first level control valve to adjust the level of the heaviersolution in the settler.

In an embodiment of the launder, the first level control valve comprisesan actuator by which the height position of the third end of the secondinlet pipe is adjustable.

In an embodiment of the launder, the launder element module comprises afeed outlet pipe having a fifth end opening to the inner space of thethird shell via a second level control valve disposed at a bottom of thethird shell, and a sixth end adapted to feed a solution to a settler.

In an embodiment of the launder, the launder module group comprises abox module comprising a first discharge box supported inside a frameworkstructure for receiving and discharging the lighter solution phase fromthe first flow channel, and a second discharge box supported inside theframework structure for receiving and discharging the heavier solutionphase from the second flow channel.

In an embodiment of the launder, the box module comprises a feed boxsupported inside the framework structure for feeding dispersion to thethird flow channel.

The conical third channel which forms a feed launder for the dispersionhas a cross section which decreases from the end connected to the feedbox towards its other end which is distant from the feed box. This hasthe advantage that the delay time distribution of the dispersion in thefeed launder is uniform so that no standing zones, in which thedispersion would separate, are formed. The bottom of the third flowchannel is inclined downwards towards the feed box, whereby the aqueoussolution separated from the dispersion in the feed launder flows back tothe mixer via the feed box.

In an embodiment of the launder, the framework structure comprises afirst end frame comprising: a horizontal first lower beam; a horizontalfirst upper beam at a distance from the first lower beam; a verticalfirst corner post which is fixedly connected to a first end of the firstlower beam, defining a first corner, the vertical first corner postbeing fixedly connected to a first end of the first upper beam, defininga second corner; and a vertical second corner post at a distance fromthe first corner post, the vertical second corner post being fixedlyconnected to a second end of the first lower beam, defining a thirdcorner, the vertical second corner post being fixedly connected to asecond end of the first upper beam, defining a fourth corner. Further,the framework structure comprises a second end frame comprising ahorizontal second lower beam; a horizontal second upper beam at adistance from the second lower beam; a vertical third corner post whichis fixedly connected to a first end of the second lower beam, defining afifth corner, the vertical third corner post being fixedly connected toa first end of the second upper beam, defining a sixth corner; and avertical fourth corner post at a distance from the third corner post,the vertical fourth corner post being fixedly connected to a second endof the second lower beam, defining a seventh corner, the vertical fourthcorner post being fixedly connected to a second end of the second upperbeam, defining an eighth corner. Further, the framework structurecomprises a first bottom side rail fixedly connected to the first endframe at the first corner and to the second end frame at the fifthcorner; a second bottom side rail fixedly connected to the first endframe at the third corner and to the second end frame at the seventhcorner; a first top side rail fixedly connected to the first end frameat the second corner and to the second end frame at the sixth corner; asecond top side rail fixedly connected to the first end frame at thefourth corner and to the second end frame at the eighth corner; bottomcross members fixedly connected between and to the first and secondbottom side rails; top cross members fixedly connected between and tothe first and second top side rails; side cross members fixedlyconnected between and to the bottom side rails and the top side rails. Acorner fitting is attached to each of the first corner, second corner,third corner, fourth corner, fifth corner, sixth corner, seventh cornerand eighth corner.

In an embodiment of the launder, the launder comprises a foundation onwhich the launder module group is supported at a height above the groundlevel, thereby providing a space for piping and access below thesettler.

In an embodiment of the launder, the foundation comprises a plurality ofpillars having ISO shipping standard compatible container lashingfittings to which the corner fittings of the launder element modules canbe connected. The installation of the launder on pillars has theadvantage that a minimal amount of excavation work is needed. Theinstallation on piltars also makes it possible to speed up theinstallation and shortens the project lead time. Pillars also allow easyassembly and disassembly of the modules and launders. When more capacityis needed for the launder, it is easy to increase capacity by simplyadding more pillars for the installation of more modules. The increasingof capacity can be done with a short interruption of the process.

In an embodiment of the launder, the pillar comprises a lower end whichis supported on the ground, an upper end, and one or more containerlashing fittings attacked to the upper end of the pillar.

In an embodiment of the launder, the container lashing fitting comprisesa stacking cone.

In an embodiment of the launder, the container lashing fitting comprisesa twist lock.

In an embodiment of the launder, the pillar comprises one to fourcontainer lashing fittings depending on the number of corner fittings tobe connected onto the pillar.

In an embodiment of the launder, the pillar comprises a plastic tube, aconcrete reinforcement arranged inside the plastic tube, cast concretecast inside the plastic tube, and a metal base plate attached at theupper end of the pillar, to which base plate one or more containerlashing fittings are fixedly connected.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and constitute a part of thisspecification, illustrate embodiments of the invention and together withthe description help to explain the principles of the invention. In thedrawings:

FIG. 1 is an axonometric schematic view of a solvent extraction settlerequipped with a launder according to an embodiment of the presentinvention,

FIG. 2 is an axonometric view of the framework structure of the launderelement module of FIG. 1,

FIG. 3 is an axonometric view of detail A of FIG. 2,

FIG. 4 is an axonometric view of three interconnected launder modules ofFIG. 1,

FIG. 5 is a side view of the launder module of FIG. 4,

FIG. 6 is an end view of the three interconnected launder modules ofFIG. 3, 15

FIG. 7 is a plan view of the three interconnected launder modules ofFIG. 3, seen from above,

FIG. 8 is a view of the layout of the foundation of the settler of FIG.1,

FIGS. 9 to 12 show an axonometric view of four different types ofpillars used in the foundation of FIG. 8, the pillars being equippedwith stacking cones as container lashing fittings,

FIGS. 13 and 14 show another embodiment of the pillar equipped with atwist lock as a container lashing fitting, and

FIG. 15 shows a schematic longitudinal section of the pillar.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows one embodiment of a solvent extraction settler which isused in hydrometallurgical liquid-liquid extraction processes forseparating solutions mixed in a dispersion into different solutionphases. The launder 1 is connected to the settler 2. The dispersion pumpand mixers which are used to prepare the dispersion are not shown inFIG. 1. The settler 2, which is not part of this invention, is shownonly schematically. The settler 2 may be of a conventional typecomprising a large tank built on the site, or it may be modular andcomposed of a number of pre-fabricated, ISO shipping containercompatible settler element modules transferred and installed at the siteinto a complete settler as disclosed in another patent aplication filedin parallel with this aplication.

The launder 1 may have two functions. It may be arranged to feeddispersion to the settler 2 (see FIG. 4) and it may be arranged toreceive and discharge the separated solutions obtained from the settler2.

The launder 1 comprises a launder module group 5 which consists of threeself-supporting launder element modules 3 and a box module 24 arrangedin parallel and side-by-side with each other. Each launder elementmodule 3 has exterior dimensions, strength and handling and securingmeans 4 conforming to ISO shipping container standards to enable ISOcompatible transportability. The launder element module 3 comprises aself-supporting framework structure 6 having a shape of a rectangularparallelepiped with exterior dimensions and corner fittings 4 conformingto ISO shipping container standards. The corner fittings 4 are attachedto each corner of the framework structure 6. The launder element module3 conforms to standard ISO 668 Series 1 “Freightcontainers—Classification, dimensions and ratings”; and the cornerfittings 4 conform to standard ISO 1161 Series 1 “Freightcontainers—Corner fittings—specification”.

Shells 7, 8, 9 are supported inside the framework structure 6 and formatleast a part of a flow path for the solutions flowing in the launder.The shells 7, 8, 9 can be made of steel or a fibre-reinforced plasticcomposite. The shells 7, 8, 9 are tubular hollow bodies which arepreferably made of a fibre-reinforced plastic composite and preferablymanufactured by filament winding technology.

As shown in FIG. 2, the framework structure 6 encompassing the shells 7,8, 9 may have the following structure. The framework structure 6comprises a first end frame 28. The first end frame 28 comprises ahorizontal first lower beam 29, a horizontal first upper beam 30 at adistance from the first lower beam, a vertical first corner post 31which is fixedly connected to a first end of the first lower beam 29,defining a first corner 32, the vertical first corner post 31 beingfixedly connected to a first end of the first upper beam 30, defining asecond corner 33, a vertical second corner post 34 at a distance fromthe first corner post 31, the vertical second corner post being fixedlyconnected to a second end of the first lower beam 29, defining a thirdcorner 35, the vertical second corner post 34 being fixedly connected toa second end of the first upper beam 30, defining a fourth corner 36.The framework structure 7 comprises a second end frame 37. The secondend frame 37 comprises a horizontal second lower beam 38, a horizontalsecond upper beam 39 at a distance from the second lower beam 38, avertical third corner post 40 which is fixedly connected to a first endof the second lower beam 38, defining a fifth corner 41, the verticalthird corner post 40 being fixedly connected to a first end of thesecond upper beam 39, defining a sixth corner 42, and a vertical fourthcorner post 43 at a distance from the third corner post 40, the verticalfourth corner post being fixedly connected to a second end of the secondlower beam 39, defining a seventh corner 44, the vertical fourth cornerpost being fixedly connected to a second end of the second upper beam39, defining an eighth corner 45. A first bottom side rail 46 is fixedlyconnected to the first end frame 28 at the first corner 32 and to thesecond end frame 37 at the fifth corner 41. A second bottom side rail 47is fixedly connected to the first end frame 28 at the third corner 35and to the second end frame 37 at the seventh corner 44. A first topside rail 48 is fixedly connected to the first end frame 28 at thesecond corner 33 and to the second end frame 37 at the sixth corner 42.A second top side rail 49 is fixedly connected to the first end frame 28at the fourth corner 36 and to the second end frame 37 at the eighthcorner 45. Bottom cross members 50 are fixedly connected between and tothe first and second bottom side rails 46, 47. Top cross members 51 arefixedly connected between and to the first and second top side rails 48,49. Side cross members 52 are fixedly connected between and to thebottom side rails 46, 47 and the top side rails 48, 49. A corner fitting4 is attached to each of the first corner 32, second corner 33, thirdcorner 35, fourth corner 36, fifth corner 41, sixth corner 42, seventhcorner 44 and eighth corner 45.

The framework structure 6 conforms to standard ISO 668 Series 1 “Freightcontainers—Classification, dimensions and ratings”. The frameworkstructure 6 may preferably have an external length of 6.058 m (20 ft) or2.991 m (10 ft) and a width of 2.438 m (8 ft).

FIG. 3 shows a corner fitting 4 fixedly connected to a corner of theframework structure 6. The corner fittings 4 conform to standard ISO1161 Series 1 “Freight containers—Corner fittings—specification”. Thecorner fitting 4 has a connecting hole at each of its three sides.

As can be seen in FIGS. 4 to 7, each launder element module 3 comprisesa first shell 7 to receive and conduct a light solution phase. Further,the launder element module 3 comprises a second shell 8 to receive andconduct a heavy solution phase. Further, the launder element module 3comprises a third shell 9 adapted to feed dispersion to a next settler2, as is seen in FIG. 4.

With reference to FIGS. 4 and 7, the launder module group 5 of the shownembodiment comprises three launder element modules 3. The first shells 7of the adjacently neighboring launder modules 3 are abutting andconnected to each other to form a first flow channel 10. The secondshells 8 of the adjacently neighboring launder modules are abutting andconnected to each other to form a second flow channel 11. The thirdshells 9 of the adjacently neighboring launder modules are abutting andconnected to each other to form a third flow channel 12. The firstshells 7 are conical so that the sequentially connected first shells 7of the launder element modules 3 in the launder module group 5 togetherform a conical first flow channel 10. The second shells 8 are conical sothat the sequentially connected second shells 8 of the launder elementmodules 3 in the launder module group 5 together form a conical secondflow channel 11. The third shells 9 are conical so that the sequentiallyconnected third shells 9 of the launder element modules 3 in the laundermodule group 5 together form a conical third flow channel 12.

As seen in FIG. 1 the module group 5 comprises also a box module 24. Thebox module 24 comprises a self-supporting framework structure 6 having ashape of a rectangular parallelepiped with exterior dimensions andcorner fittings 4 conforming to ISO shipping container standards, thecorner fittings 4 being attached to each corner of the frameworkstructure 6. A first discharge box 23 is supported inside the frameworkstructure 6 for receiving and discharging the lighter solution phasefrom the first flow channel 10. The box module 24 also comprises asecond discharge box 26 supported inside the framework structure 6 forreceiving and discharging the heavier solution phase from the secondflow channel 11. Further, the box module 5 comprises a feed box 27supported inside the framework structure 6 for feeding dispersion to thethird flow channel 12. The framework structure 6 of the box module 24may be similar to that shown and disclosed in connection with FIG. 2.

The conical first and second flow channels 10 and 11 which formdischarge channels for the lighter solution (normally organic) and theaqueous solution have many inlets along their length. The cross sectionof the conical first and second flow channels 10, 11 increases and theirbottom is inclined downwards towards the first and second dischargeboxes 25, 26. In operation, after each inlet, the flow rate in the firstand second flow channels 10, 11 increases. In a conical launder the flowrate remains the same for the whole length of the launder and no returneddies and standing flows are created. Thereby crud accumulation isavoided if the solutions contain solids.

The conical third channel 12 which forms a feed launder for thedispersion has a cross section which decreases from the end connected tothe feed box 27 towards its other end which is distant from the feed box27. This has the advantage that the delay time distribution of thedispersion in the feed launder 12 is uniform so that no standing zones,in which the dispersion would separate, are formed. The bottom of thethird flow channel 12 is inclined downwards towards the feed box 27whereby the aqueous solution separated from the dispersion in the feedlaunder 12 flows back to the feed box and further to the mixer.

Due to the conical form of the shells 7, 8, 9 which form the flowchannels 10, 11, 12, each launder element module 3 is different from theother due to different sizes of the shells 7, 8, 9. However, the systemmay be based on e.g. 14 standard elements which can be configured to aflow rate range of 150 to 8000 m³/h. The full length conical flowchannel 10, 11, 12 may be manufactured as one piece on a mold ormandrel, and thereafter the flow channel can be cut into separate partshaving lengths which fit inside the framework structure 6, and the partsare then installed inside the framework structures 6 of the launderelement modules 3. The interconnection of the shells can be made bynormal means and methods of connecting plastic tubes, such as by usingconnecting sleeves and/or by gluing the abutting ends together.

Referring to FIGS. 4 and 5, the launder element module 3 comprises afirst inlet pipe 12 having a first end 13 opening to the inner space ofthe first shell 7 and a second end 14 opening to the settler 2 on theright hand side of FIG. 4. The second end 14 is adapted to receive thelight solution phase as an overflow from the settler 2 on the right handside of FIG. 4. Further, the launder element module 3 comprises a secondinlet pipe 15 having a third end 16 opening to the inner space of thesecond shell 8 at a bottom of the second shell 8, and a fourth end 18opening to the settler 2. The fourth end 18 is adapted to receive theheavy solution phase as an underflow from the settler. The overflowheight position of the third end 16 of the second inlet pipe 15 insidethe second shell 8 is adjustable by a first level control valve 17 toadjust the level of the heavier solution in the settler 2. The firstlevel control valve 17 comprises an actuator 19 by which the heightposition of the third end 16 of the second inlet pipe 15 is adjustable.Further, the launder element module 3 comprises a feed outlet pipe 20having a fifth end 21 opening to the inner space of the third shell 9via a second level control valve 22 disposed at a bottom of the thirdshell, and a sixth end 23 adapted to feed a solution to a settler 2 onthe left hand side of FIG. 4.

FIG. 8 shows a layout of the foundation designed for the whole settler 2including the launder module group 5 shown in FIG. 1. The laundercomprises a foundation 53 on which the module group 5 is supported at aheight above the ground level, thereby providing a space for piping andaccess underneath the launder. The foundation 53 comprises a pluralityof pillars 54 having ISO shipping standard compatible container lashingfittings 55, 56 to which the corner fittings 4 of the launder modules 3and the box module 24 can be connected.

The pillar 54 comprises a lower end 57 which is supported on the ground,an upper end 58, and one or more container lashing fittings 55, 55attached to the upper end 58 of the pillar 54.

FIGS. 9 and 15 show that the pillar 54 comprises a lower end 57supported on the ground and an upper end 58. One or more containerlashing fittings 55, 56 are attached to the upper end 58. As illustratedin FIGS. 9 to 12, the pillar 54 may comprise one to four containerlashing fittings 55, 56 depending on the number of corner fittings 4 tobe connected onto the pillar. A pillar 54 supporting one corner of themodule comprises only one container lashing fitting 55 (FIG. 9). Apillar 54 supporting two corners of parallel modules comprises a pair ofcontainer lashing fittings 55 arranged side by side (FIG. 10). A pillar54 supporting two corners of sequential modules comprises a pair ofcontainer lashing fittings 55 arranged in a row (FIG. 11). A pillar 54supporting four corners of parallel and sequential modules comprises twopairs of container lashing fittings 55 (FIG. 12). The container lashingfittings may be stacking cones 55 as shown in FIGS. 9 to 12, oralternatively, they may be twist locks 56 as shown in FIGS. 13 and 14.

With reference to FIG. 15, the pillar 54 comprises a plastic tube 59, aconcrete reinforcement of metal 60 arranged inside the plastic tube 59,cast concrete 61 cast inside the plastic tube, and a metal base plate 62attached at the upper end of the pillar, to which base plate one or morecontainer lashing fittings 55, 56 are fixedly connected.

The launder 1 is manufactured so that that at the site of manufacture,such as in an engineering workshop, a plurality of self-supportinglaunder element modules 3, 24 are manufactured. Each launder elementmodule 3, 24 has exterior dimensions, strength and handling and securingmeans 4 conforming to ISO shipping container standards. The launderelement modules 3 are transported to the site of installation as normalfreight by transport equipment, such as trucks, trailers and containerships, capable of handling and transporting ISO compatible units. At thesite of installation the launder element modules 3 are assembled into amodule group 5 which forms a complete launder 1.

Although the invention has been the described in conjunction with acertain type of launder, it should be understood that the invention isnot limited to any certain type of launder. While the present inventionshave been described in connection with a number of exemplary embodimentsand implementations, the present inventions are not so limited, butrather cover various modifications and equivalent arrangements, whichfall within the purview of the prospective claims.

1. A method of manufacturing a launder to be used in cooperation with asolvent extraction settler adapted for hydrometallurgical liquid-liquidextraction processes, in which method the launder is installed at thedischarge end of the settler, characterized in that the method comprisesthe steps of: manufacturing at the site of manufacture, a plurality ofself-supporting launder element modules, each conforming to shippingcontainer standards, transporting the launder element modules to thesite of installation as normal freight by transport equipment, such astrucks, trailers and container ships, capable of handling andtransporting shipping standard compatible units, and assembling at thesite of installation the launder element modules into a module groupforming a complete launder.
 2. A launder to be used in cooperation witha solvent extraction settler adapted for hydrometallurgicalliquid-liquid extraction processes, characterized in that the laundercomprises a launder module group consisting of self-supporting launderelement modules, each conforming to shipping container standards toenable shipping container standard compatible transportability.
 3. Thelaunder according to claim 2, where launder is arranged to feeddispersion to a solvent extraction settler.
 4. The launder according toclaim 2, where launder is arranged to receive and discharge solutionphases separated in the solvent extraction settler.
 5. The launderaccording to claim 2 where the launder element module comprises aself-supporting framework structure having a shape of a rectangularparallelepiped with exterior dimensions and corner fittings conformingto ISO shipping container standards, said corner fittings being attachedto each corner of the frame-work structure, and a shell which issupported inside the framework structure and forms at least a part of aflow path for the solutions flowing in the launder.
 6. The launderaccording to claim 2 where the launder element module conforms tostandard ISO 668 Series 1 “Freight containers—Classification, dimensionsand ratings”; and where the corner fittings conform to standard ISO 1161Series 1 “Freight containers—Corner fittings—specification”.
 7. Thelaunder according to claim 2 where the shell is a tubular hollow bodymade of a fibre-reinforced plastic composite.
 8. The launder accordingto claim 2 where the module group comprises two or more launder elementmodules arranged in parallel and side by side with each other.
 9. Thelaunder according to claim 2 the launder element module comprises afirst shell to receive and conduct a light solution phase, and a secondshell to receive and conduct a heavy solution phase.
 10. The launderaccording to claim 9, where the launder element module comprises a thirdshell adapted to feed dispersion to a next settler.
 11. The launderaccording to claim 9, where the launder module group comprises aplurality of launder element modules, and where the first shells of theadjacently neighboring launder modules are abutting and connected toeach other to form a first flow channel, and the second shells of theadjacently neighboring launder modules are abutting and connected toeach other to form a second flow channel.
 12. The launder according toclaim 11, where the first shells are conical so that the sequentiallyconnected first shells of the launder element modules in the laundermodule group together form a conical first flow channel.
 13. The launderaccording to claim 11, where the second shells are conical so that thesequentially connected second shells of the launder element modules inthe launder module group together form a conical second flow channel.14. The launder according to claim 10 where the third shells are conicalso that the sequentially connected third shells of the launder elementmodules in the launder module group together form a conical third flowchannel.
 15. The launder according to claim 9 where the launder elementmodule comprises a first inlet pipe having a first end that opens to theinner space of the first shell and a second end that opens to thesettler, the second end being adapted to receive the light solutionphase as an overflow from the settler.
 16. The launder according toclaim 9 where the launder element module comprises a second inlet pipehaving a third end that opens to the inner space of the second shell ata bottom of the second shell, and a fourth end that opens to thesettler, the fourth end being adapted to receive the heavy solutionphase as an undertow from the settler.
 17. The launder according toclaim 16, where overflow height position of the third end of the secondinlet pipe inside the second shell is adjustable by a first levelcontrol valve to adjust the level of the heavier solution in thesettler.
 18. The launder according to claim 17, where the first levelcontrol valve comprises an actuator by which the height position of thethird end of the second inlet pipe is adjustable.
 19. The launderaccording to claim 9 where the launder element module comprises a feedoutlet pipe having a fifth end opening to the inner space of the thirdshell via a second level control valve disposed at a bottom of the thirdshell, and a sixth end adapted to feed a solution to a settler.
 20. Thelaunder according to claim 18, where the launder module group comprisesa box module comprising a first discharge box supported inside aframework structure for receiving and discharging the lighter solutionphase from the first flow channel, and a second discharge box supportedinside the framework structure for receiving and discharging the heaviersolution phase from the second flow channel.
 21. The launder accordingto claim 20, where the box module comprises a feed box supported insidethe framework structure for feeding dispersion to the third flowchannel.
 22. The launder according to claim 2 where the frameworkstructure comprises a first end frame comprising: a horizontal firstlower beam, a horizontal first upper beam at a distance from the firstlower beam, a vertical first corner post fixedly connected to a firstend of the first lower beam, defining a first corner, the vertical firstcorner post fixedly connected to a first end of the first upper beam,defining a second corner, a vertical second corner post at a distancefrom the first corner post, the vertical second corner post fixedlyconnected to a second end of the first lower beam, defining a thirdcorner, the vertical second corner post fixedly connected to a secondend of the first upper beam, defining a fourth corner, a second endframe (37) comprising a horizontal second lower beam, a horizontalsecond upper beam at a distance from the second lower beam, a verticalthird corner post fixedly connected to a first end of the second lowerbeam, defining a fifth corner, the vertical third corner post fixedlyconnected to a first end of the second upper beam, defining a sixthcorner, a vertical fourth corner post at a distance from the thirdcorner post, the vertical fourth corner post being fixedly connected toa second end of the second lower beam, defining a seventh corner, thevertical fourth corner post fixedly connected to a second end of thesecond upper beam, defining an eighth corner, a first bottom side railfixedly connected to the first end frame at the first corner and to thesecond end frame at the fifth corner, a second bottom side rail fixedlyconnected to the first end frame at the third corner and to the secondend frame at the seventh corner, a first top side rail fixedly connectedto the first end frame at the second corner and to the second end frameat the sixth corner, a second top side rail fixedly connected to thefirst end frame at the fourth corner and to the second end frame at theeighth corner, bottom cross members fixedly connected between and to thefirst and second bottom side rails, top cross members fixedly connectedbetween and to the first and second top side rails, side cross membersfixedly connected between and to the bottom side rails and the top siderails, and that a corner fitting is attached to each of the firstcorner, second corner, third corner, fourth corner, fifth corner, sixthcorner, seventh corner and eighth corner.
 23. The launder according toclaim 2 where the launder comprises a foundation on which the laundermodule group is supported at a height above the ground level, therebyproviding a space for piping and access underneath the settler.
 24. Thelaunder according to claim 23, where the foundation comprises aplurality of pillars having ISO shipping standard compatible containerlashing fittings to which the corner fittings of the launder elementmodules can be connected.
 25. The launder according to claim 24, wherethe pillar comprises a lower end supported on the ground, an upper end,and one or more container lashing fittings attached to the upper end ofthe pillar.
 26. The launder according to claim 25, where the containerlashing fitting comprises a stacking cone.
 27. The launder according toclaim 25, where the container lashing fitting comprises a twist lock.28. The launder according to claim 25 where the pillar comprises atleast one container lashing fitting, where the number of container lashfittings depend on the number of corner fittings to be connected ontothe pillar.
 29. The launder according to claim 25 where the pillarcomprises a plastic tube, a concrete reinforcement arranged inside theplastic tube, cast concrete cast inside the plastic tube, and a metalbase plate attached at the upper end of the pillar, to which base plateone or more container lashing fittings are fixedly connected.